The invention relates to a poor-scatter pot magnet system for magnetic-dynamic loudspeakers or acoustic transducers.
Poor-scatter magnet systems have already been customary for building into television receivers or for a use in the vicinity of ferrite antennas. At the same time, always two permanent magnets (ring and plate) are built into a completely closed iron pot which, with its upper edge, encloses nearly the upper pole plate of the magnet system. As a result of the fact that the magnet ring and the magnet plate are magnetized in an opposite direction and the magnetic system is completely screened off as a result of the potshaped housing, there results hitherto already a decrease of the magnetic scattering effect which, in the case of most types in a measuring distance according to DIN 45 578 (the German Standardization Institute paper entitled: "Magnet System For Moving Coil Loudspeakers: definitions, dimensions, methods of measurement) of 100 mm from the pole core center amounts to less than 1 A/cm. The unit A/cm is Amperes/centimeter, a unit of a magnetic field H in the International System of units. For this type of measurement, formerly the "Oersted" was used. Such magnetic systems poor in scattering are therefore used particularly in television devices in the case of which the magnetic scatter field would lead to the distortion of the television picture on the picture tube.
As a result of the continuously progressing development in the field of television and radio engineering, television devices nowadays are however no longer equipped with only one but with several loudspeakers so that the space available in the housing of the television devices becomes ever tighter. The loudspeaker magnets move more closely to the picture tube so that the magnetic scattering of the known loudspeaker system becomes evermore problematic.